As Dutch voters went to the polls on Wednesday, a swath of international high-profile Twitter accounts posted content supporting Turkish President Recep Tayyip Erdogan in his feud with Germany and the Netherlands, with hashtags reading, in Turkish, “NaziGermany” and “NaziHolland”

The messages and swastikas appeared on the verified Twitter accounts of German newspaper Die Welt, Forbes Magazine, BBC North America, and Reuters Japan. Also targeted the Twitter accounts of the Unicef USA, European Parliament, French politicians like Alain Juppé, Sprint Corp.’s Chief Executive Officer and President Marcelo Claure, among others.

The tweets included a swastika and described the attack as a “little Ottoman slap”.

“See you on April 16,” they read, referring to the date of Turkey’s referendum to grant more powers to Erdogan, and finish with: “What did I write? Learn Turkish.”

A four-minute video attached to the tweets begins with an Erdogan speech in which he says: “If we’re going to die, let’s die like men.”

It then features scenes from various Erdogan speeches, starting with his showdown with then-Israeli President Shimon Peres in Davos in 2009, as a campaign song chanting his name, “Recep Tayyip Erdogan,” plays in the background.

BBC North America has since tweeted that it “temporarily lost control” of its account, but normal service has resumed. Some of the tweets have been deleted.

An Amsterdam-based startup said it’s investigating if it’s the source of the postings. Twitter Counter, a marketing tool that allows people and companies to track their popularity on Twitter, said it blocked people from postings through its system while it studied the issue.

“We are aware of the situation and have started an investigation into the matter.”

Twitter Counter reported an attack in November in which accounts from Sony Corp., Viacom Inc., Microsoft Corp. and others were compromised and posting spam messages. Twitter Counter apologised and said it had fixed the problem.

“We are aware of an issue affecting a number of account holders this morning,” said Twitter Inc. company spokeswoman Kaori Saito.

“We quickly located the source which was limited to a third party app. We removed its permissions immediately. No additional accounts are impacted.”

Ginor said the company had reached “95 per cent certainty” that it had fixed the problem after being hacked in November. The company couldn’t be sure a hacker was “still lurking in the shadows, just waiting for the opportunity.”

The incidents show the indirect ways hackers can take over a company’s Twitter feed. Twitter Counter is one of many companies that plug into Twitter to provide marketing and analytics tools for people, businesses and other groups. Companies including Time Inc., Netflix Inc., Chevron Corp. and YouTube use Twitter Counter, according to its website.